Clutch Instead of Torque Convertor

[SmokeShow]

Mike, I keep hearing rumor of a particular pulling truck being built that has an allison transmission in it BUT instead of a traditional torque converter connecting it to the engine, it has a clutch setup.

1) Is this type of thing done on ANY automatic transmissions?
2) If yes, can it actually be done with an allison 1000? physically or even theoretically?
3) Do you know about this or of any others that might be doing this?



C-ya

 

[dmax lb7]

I know this kind of set up is used in some class 8 trucks. Push in the clutch to stop, let it out and the trans. does the shifting.

 

[LBZ]

Mercedes has a trans that does this in a few of their big trucks. So I guess it is possible but sounds like a lot of manufacturing to build one for an ally.

An electric controlled clutch set-up controlled by the TCM would work, but i'm not sure if it could actuate fast enough.

Interesting idea Mitch.

 

[Stingpuller]

Trans

They used to make a clutch turbo and clutch flite trans like that in the 70's. They were cool. You machined the bell off and bolted a blowproof on with a adapter. They were hard on parts as there is no fluid coupler and did seem to leak a little. I would love to see that on a ally. Jeff

 

[SmokeShow]

money isn't an object for the guy that's supposedly done this. He spent oodles just dominate work stock. I expect a show-stopper when it's done. Supposed to be a 3.0 truck.

 

[Mike L.]

I have not heard of it with an Alli. If I was going to do this it shure as hell wouldn't be an Alli as there are better transmissions for this kind of setup.

 

[Noreaster]

money isn't an object for the guy that's supposedly done this. He spent oodles just dominate work stock. I expect a show-stopper when it's done. Supposed to be a 3.0 truck.

Isn't that a trophy only class?

 

[knagel]

I know this kind of set up is used in some class 8 trucks. Push in the clutch to stop, let it out and the trans. does the shifting.

These are called automatics but they are just 100% computer controlled manual transmissions. You push the clutch down, pull the shifter in D and release the clutch then the computer takes over and takes fuel away on shifts the engages a selonoid on the trans for the next shift. Insted of your hand makeing the shift it is the computer and selonoid up shifting and down shifting the manual trans shift forks where the stick normally goes.

 

[keith2500hd]

wonder if it might be heavy duty drag powerglide(reid case) with input adapter that splines to clutch disc, similar to dragboat setups.

 

[IdahoRob]

I grew up with a guy that had a blown 1969 chevelle. He had a clutched auto tranny. I don't remember what kind it was though.

 

[Fingers]

We already have this ability with the lock up converters. The TCM already does a regulated apply. With some tweeking, you get near manual response. Just need to find a way to get it to lock in 1'st

 

[Leadfoot]

We already have this ability with the lock up converters. The TCM already does a regulated apply. With some tweeking, you get near manual response. Just need to find a way to get it to lock in 1'st

Not knowing that much about Allison's, what is it that won't allow lockup in First? Is it a mechanical limitation (valve body) or is it an electronic issue?

 

[racinmike77]

use two washers and shim your converter flow valve to about .150 dont ask me how I know it wont lock the converter but it will definately give the truck some interesting street manners, I think it kinda simulates running a tighter converter

 

[Fingers]

Not knowing that much about Allison's, what is it that won't allow lockup in First? Is it a mechanical limitation (valve body) or is it an electronic issue?

It is the TCM programming that prevents 1'st gear lock up. AFAIK no one has really cracked the TCM code past looking at and modifying the tables.

 

[Mike L.]

use two washers and shim your converter flow valve to about .150 dont ask me how I know it wont lock the converter but it will definately give the truck some interesting street manners, I think it kinda simulates running a tighter converter

That drags the clutch ( partial apply ) and will detroy the coverter and overheat the Alli.

 

[racinmike77]

I did not have the instructions and lost the tool when I did my suncoast 3. Found a thread on the diesel place and did what it said to shim the main pressure valve, the thread was either incorrect or I looked at the picture the wrong way and It ran like this for a couple thousand miles wasnt too bad just a pain to hold back at a stoplight and first gear was real ly jumpy. Tried an 03 TCM it seemed to help but eventually had to tear into the trans to fix it.

 

[racinmike77]

check this out this is the picture I used http://www.dieselplace.com/forum/showthread.php?t=221769&highlight=pressure+shim due to my lack of attentiveness and attention to detail I put a shim on #8 instead of #22

 

[Mike L.]

Looks like someone goofed when they said to put the shim on # 8.

 

[duratothemax]

I dont think 1st gear lockup is hydraulically possible on the allison. If you ground the f-trim solenoid control wire in first gear nothing happends. It only locks up once it shifts into second.

ben

 

[Mike L.]

I dont think 1st gear lockup is hydraulically possible on the allison. If you ground the f-trim solenoid control wire in first gear nothing happends. It only locks up once it shifts into second.

ben

You cannot get lock up in first gear because of the positioning of the shift valves in the valve body. It can be done but would be a huge project that would never pay for itself.